A number of inconsistent and often polar behavioral findings have been reported following interference with brain norepinephrine (NE) function. Thus, precisely the same manipulations of NE have been observed to cause depression, no change or facilitation of a variety of behaviors. We believe that these apparent disparities may actually reflect an interaction between NE- and dopamine (DA)-containing neurons and it is this hypothesis which we wish to investigate. The study of possible NE-DA interactions will be carried out on both behavioral and biochemical levels. The behaviors to be examined in these studies are: a) male sexual behavior, 2) electrical self-stimulation of the brain, 3) feeding. Pharmacological and surgical interventions designed primarily to interfere with NE function will be used. Behavioral and biochemical effects of these treatments will be examined under both activating, or stressful conditions and, relatively non-activating conditions. Biochemical measurements will include the determination of dopamine-beta-hydroxylase and 3-methoxy-4-hydroxyphenylglycol to assess NE activity and homovanillic acid and dihydroxyphenylacetic acid as a reflection of the activity of DA-containing neurons. These will be examined in appropriate brain regions. We also propose to continue the study of stress-related consummatory behaviors. Emphasis will be placed on trying to understand the biochemical events underlying the temporary stress-induced recovery of function observed in animals with lateral hypothalamic lesions.